Opinions and suggestions on how far to go with engine rebuild

[KZ]

In a few weeks I will travel to the engine shop and meet with the guys who have my 1970 440-6 engine. As I have stated from my previous posts, I want to keep the restoration of the entire project (70 Challenger RT/SE 440-6) to as close to original as possible. But wanted to get some feedback as to what you folks did with your engines, or what suggestions you may have for me to maybe eke out a few more ponies. I want the engine to be able to run on premium pump gas so I know at the very least the valve seats need to be replaced. I have not had a cylinder leakage test or compression test performed so not sure about the innards but the motor only has 44000 miles. I have had the car since 1981 and have only put 1800 miles on it. I would love to keep same pistons, crankshaft, camshaft, etc. again, original. The engine shop has been rebuilding engines professionally since 1962, aside from the obvious, i.e. blueprint, balance, all new gaskets, seals, etc. I was going to ask they polish the intake and exhaust ports, but what else could I ask them to do to increase power without risk of pre-ignition, detonation or cracked water jackets? How much engine work can be done below before you have to have the 6-pack re-jetted?

BTW, the HP for the 440-6 is stated as 390, is that at the crankshaft end or what is actually at the rear wheels, my gut tells me the former and not the latter. The Chally is kind of svelte so it would be nice to have more HP actually getting to the rear wheels.

Thanks

[blown motor]

Can you machine the block or the heads to increase compression?

[HP_Cuda]

Well if you want to keep most things original, you could try doing port matching between the intake and exhaust. You could do the same on the exhaust side and then you could work on the 6 pack to make sure it's setup right.

Hard to increase horsepower when you want to stick to a stock build (no cam change, head porting, carb, headers, etc)

[jimynick]

Just a question: Who, other than yourself and the engine builder, would ever know what's inside your engine? Also, remember that back in the day, 44k was halfway worn out. Remember that an engine is just an air pump- the more in and out, the more HP. So, why not have the heads- if you're obsessed with retaining the originals- CNC ported, put in a bigger valve, machine them for a bigger and better spring, run a higher ratio rocker arm, run a better cam (and CP can help there), run a piston that has a zero deck height, coatings and thinner rings and have it all inside the stock appearing block. Polish the beams and shot peen the rods, run good bolts and have a stout 440 that won't puke if you get on it. It's not cheap, but if the engine boys have been in the game since 62, none of this should surprise them. Good luck 

[Tower Rat 95B]

 Blue prints is a waste of money inmop, I did the same engine (440 Six Pack) 35 years ago, balance everything, valve job with new bronze guides also welded in a windage tray, engine was all stock except a 509 purple cam, and a orange box electronic  and big tube headers, plenty of power and always pump gas .

[Chryco Psycho]

All good suggestions .
 Cam for sure will gain some power
 Porting the heads could get 35 HP or so + porting exhaust manifolds & intake .
 You asked what I did , well mine is stroked to 512 CI with ported closed chamber heads large valves , ported intake & exhaust manifolds & Lunati solid cam , still looks stock from the outside !! A similar build made 398 Hp & 460 ft lbs measured at the rear wheels On a Mustang dyno [which read on the lower end] at 4000 ' altitude

[cudabob496]

All good suggestions .
 Cam for sure will gain some power
 Porting the heads could get 35 HP or so + porting exhaust manifolds & intake .
 You asked what I did , well mine is stroked to 512 CI with ported closed chamber heads large valves , ported intake & exhaust manifolds & Lunati solid cam , still looks stock from the outside !! A similar build made 398 Hp & 460 ft lbs measured at the rear wheels On a Mustang dyno [which read on the lower end] at 4000 ' altitude

what is your CR and cam specs?

[1 Wild R/T]

If your idea set on original heads than ignore this but if you need stock looking heads but since no one can read Pt #s with there valve covers attached I'd grab a set of 915"s stock the chamber comes in around 84cc's, have some bowl work done... Stock 70 440-6 piston is probably .040 in the hole, measure to find out... Deck the block to put the pistons .020 in the hole.. 021 steel shim gasket... Grab a Mr Sixpack cam...

True 10.2 C/R, tight quench so detonation isn't an issue... Basically a stock style "Ringer"....... One of those for all appearances "Stock" 440's, compression is just what Chrysler advertised, Cam is "Stock"... Just runs like a raped ape.....

[cudabob496]

If your idea set on original heads than ignore this but if you need stock looking heads but since no one can read Pt #s with there valve covers attached I'd grab a set of 915"s stock the chamber comes in around 84cc's, have some bowl work done... Stock 70 440-6 piston is probably .040 in the hole, measure to find out... Deck the block to put the pistons .020 in the hole.. 021 steel shim gasket... Grab a Mr Sixpack cam...

True 10.2 C/R, tight quench so detonation isn't an issue... Basically a stock style "Ringer"....... One of those for all appearances "Stock" 440's, compression is just what Chrysler advertised, Cam is "Stock"... Just runs like a raped ape.....

I had ported 915's on my 440, with the 484 cam. Would not say the power was that great. But I don't
know what they flowed.

[1 Wild R/T]

I had ported 915's on my 440, with the 484 cam. Would not say the power was that great. But I don't
know what they flowed.

915"s use the same port as a 906 so they are good not great, but they have closed chamber so compression is improved and quench is easily attained... If you spend the $$$ & you've got a good set of castings with minimal core shift they can flow 290+, you know almost as much as a lightly touched set of Eddies or Stealths... I wouldn't spend that much on them, just clean up the bowls & live with the 270-275 range...  If your looking for 496 type HP forget about it, but in the confines of looking & sounding stock, no stroker... 450 horses is pretty achievable...

[cudabob496]

915"s use the same port as a 906 so they are good not great, but they have closed chamber so compression is improved and quench is easily attained... If you spend the $$$ & you've got a good set of castings with minimal core shift they can flow 290+, you know almost as much as a lightly touched set of Eddies or Stealths... I wouldn't spend that much on them, just clean up the bowls & live with the 270-275 range...  If your looking for 496 type HP forget about it, but in the confines of looking & sounding stock, no stroker... 450 horses is pretty achievable...

Ya, with 1 and 7/8 headers, I think I was above 500hp

[cudabob496]

when I took the 915s off to port them, found out they only
had 1.60 inch exhaust valves.  So we went with 2.14s and 1.81s.
I guess the high performance 915s only had 1.72 exhaust valves.
915s only came out in 1967 I think.

[1 Wild R/T]

Ya, with 1 and 7/8 headers, I think I was above 500hp

To get in the 500HP range you had allot more cam, the idea of this build would be stock appearance & sounding stock....

[KZ]

thanks for your comments and suggestions, I will take all of these your comments and suggestions to the engine builder and work something out, to reply to one question, no one other than myself would know what kind of engine work had been done, but I thought for investment purposes, and for top resale value, I would keep as much of everything, including engine, as original as possible,

[4 speed fish]

If you want  it somewhat stock I would use the  voodoo cam 302 or 303.I would get a pair of 440 source heads paint them orange.I would replace the stock 440-6 rods.Those things are boat anchors.KB pistons.Electronic ignition, and maybe roller rockers.